<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title></title>
    <style type="text/css">
        body {
            padding: 20px;
            font-family: Arial;
        }
        
        .calc-wrap {
            width: 300px;
            border: 1px solid #ddd;
            border-radius: 3px;
        }
        
        .calc-operation {
            width: 100%;
            border-collapse: collapse;
        }
        
        .calc-in-out {
            width: 100%;
            padding: 10px 20px;
            text-align: right;
            box-sizing: border-box;
            background-color: rgba(250, 250, 250, .9);
        }
        
        .calc-in-out p {
            overflow: hidden;
            margin: 5px;
            width: 100%;
        }
        
        .calc-history {
            margin-left: -20px;
            font-size: 18px;
            color: #bbb;
            border-bottom: 1px dotted #ddf;
            min-height: 23px;
        }
        
        .calc-in,
        .calc-out {
            font-size: 20px;
            color: #888;
            line-height: 39px;
            min-height: 39px;
        }
        
        .calc-in {
            color: #888;
        }
        
        .calc-out {
            color: #ccc;
        }
        
        .calc-in.active,
        .calc-out.active {
            font-size: 34px;
            color: #666;
        }
        
        .calc-operation td {
            padding: 10px;
            width: 25%;
            text-align: center;
            border: 1px solid #ddd;
            font-size: 26px;
            color: #888;
            cursor: pointer;
        }
        
        .calc-operation td:active {
            background-color: #ddd;
        }
        
        .calc-operation .cls {
            color: #ee8956;
        }
    </style>
    <script src="./js/jquery-1.12.4.min.js"></script>
    <script type="text/javascript">
        $(function() {
            function Calculator($dom) {
                this.$dom = $($dom);
                // 历史运算
                this.$history = this.$dom.find('.calc-history');
                // 输入区
                this.$in = this.$dom.find('.calc-in');
                // 输出区
                this.$out = this.$dom.find('.calc-out');
                this.$operation = this.$dom.find('.calc-operation');

                // 运算符映射
                this.op = {
                    'plus': '+',
                    'minus': '-',
                    'mul': '*',
                    'div': '/'
                };
                this.opArr = ['+', '-', '*', '/'];

                // 中缀表达式
                this.infix = [];
                // 后缀表达式
                this.suffix = [];
                // 后缀表达式运算结果集
                this.result = [];
                // 存储最近的值
                this.lastVal = 0;
                // 当前已经计算等于完成
                this.calcDone = false;
                // 当前正在进行小数点点（.）相关值的修正
                this.curDot = false;

                this.init();
            }

            Calculator.prototype = {
                constructor: Calculator,
                // 初始化
                init: function() {
                    this.bindEvent();
                },
                // 绑定事件
                bindEvent: function() {
                    var that = this;

                    that.$operation.on('click', function(e) {
                        e = e || window.event;
                        var elem = e.target || e.srcElement,
                            val,
                            action;

                        if (elem.tagName === 'TD') {
                            val = elem.getAttribute('data-val') || elem.getAttribute('data-ac');
                            // 数字：0-9
                            if (!isNaN(parseInt(val, 10))) {
                                // 构建中缀表达式并显示
                                var infixRe = that.buildInfix(parseInt(val, 10), 'add');
                                that.$in.text(infixRe.join('')).addClass('active');

                                that.calculate();

                                return;
                            }

                            action = val;

                            // 操作：清除、删除、计算等于
                            if (['cls', 'del', 'eq'].indexOf(action) !== -1) {
                                if (!that.infix.length) {
                                    return;
                                }

                                // 清空数据
                                if (action === 'cls' || (action === 'del' && that.calcDone)) {
                                    that.$in.text('');
                                    that.$out.text('');

                                    that.resetData();
                                }
                                // 清除
                                else if (action === 'del') {
                                    // 重新构建中缀表达式
                                    var infixRe = that.buildInfix(that.op[action], 'del');
                                    that.$in.text(infixRe.join('')).addClass('active');

                                    that.calculate();

                                }
                                // 等于
                                else if (action === 'eq') {
                                    that.calculate('eq');

                                }
                            }
                            // 预运算：百分比、小数点、平方
                            else if (['per', 'dot', 'sq'].indexOf(action) !== -1) {
                                if (!that.infix.length || that.isOp(that.lastVal)) {
                                    return;
                                }

                                if (action === 'per') {
                                    that.lastVal /= 100;
                                } else if (action === 'sq') {
                                    that.lastVal *= that.lastVal;
                                } else if (action === 'dot') {
                                    // that.curDot = true;
                                }

                                // 重新构建中缀表达式
                                var infixRe = that.buildInfix(that.lastVal, 'change');
                                that.$in.text(infixRe.join('')).addClass('active');

                                that.calculate();
                            }
                            // 运算符：+ - * /
                            else if (that.isOp(that.op[action])) {
                                if (!that.infix.length && (that.op[action] === '*' || that.op[action] === '/')) {
                                    return;
                                }

                                var infixRe = that.buildInfix(that.op[action], 'add');
                                that.$in.text(infixRe.join('')).addClass('active');
                            }
                        }
                    });
                },

                resetData: function() {
                    this.infix = [];
                    this.suffix = [];
                    this.result = [];
                    this.lastVal = 0;
                    this.curDot = false;
                },

                // 构建中缀表达式
                buildInfix: function(val, type) {
                    // 直接的点击等于运算之后，
                    if (this.calcDone) {
                        this.calcDone = false;
                        // 再点击数字，则进行新的运算
                        if (!this.isOp(val)) {
                            this.resetData();
                        }
                        // 再点击运算符，则使用当前的结果值继续进行运算
                        else {
                            var re = this.result[0];
                            this.resetData();
                            this.infix.push(re);
                        }

                    }

                    var newVal;

                    // 删除操作
                    if (type === 'del') {
                        newVal = this.infix.pop();
                        // 删除末尾一位数
                        newVal = Math.floor(newVal / 10);
                        if (newVal) {
                            this.infix.push(newVal);
                        }

                        this.lastVal = this.infix[this.infix.length - 1];
                        return this.infix;
                    }
                    // 添加操作，首先得判断运算符是否重复
                    else if (type === 'add') {
                        // 两个连续的运算符
                        if (this.isOp(val) && this.isOp(this.lastVal)) {
                            return this.infix;
                        }
                        // 两个连续的数字
                        else if (!this.isOp(val) && !this.isOp(this.lastVal)) {
                            newVal = this.lastVal * 10 + val;
                            this.infix.pop();
                            this.infix.push(this.lastVal = newVal);

                            return this.infix;
                        }
                        // 首个数字正负数
                        if (!this.isOp(val) && this.infix.length === 1 && (this.lastVal === '+' || this.lastVal === '-')) {
                            newVal = this.lastVal === '+' ? val : 0 - val;
                            this.infix.pop();
                            this.infix.push(this.lastVal = newVal);

                            return this.infix;
                        }

                        this.infix.push(this.lastVal = val);
                        return this.infix;
                    }

                    // 更改操作，比如%的预运算
                    else if (type === 'change') {
                        this.infix.pop();
                        this.infix.push(this.lastVal = val);

                        return this.infix;
                    }

                },
                // 判断是否为运算符
                isOp: function(op) {
                    return op && this.opArr.indexOf(op) !== -1;
                },
                // 判断运算符优先级
                priorHigher: function(a, b) {
                    return (a === '+' || a === '-') && (b === '*' || b === '/');
                },
                // 进行运算符的运算
                opCalc: function(b, op, a) {
                    return op === '+' ?
                        a + b :
                        op === '-' ?
                        a - b :
                        op === '*' ?
                        a * b :
                        op === '/' ?
                        a / b :
                        0;
                },
                // 即时得进行运算
                calculate: function(type) {
                    this.infix2Suffix();
                    var suffixRe = this.calcSuffix();

                    if (suffixRe) {
                        this.$out.text('=' + suffixRe)
                            .attr('title', suffixRe)
                            .removeClass('active');

                        // 如果是直接显示地进行等于运算
                        if (type === 'eq') {
                            this.$in.removeClass('active');
                            this.$out.addClass('active');
                            // 设置标记：当前已经显示地进行计算
                            this.calcDone = true;
                            this.lastVal = suffixRe;
                            // 设置历史记录
                            var history = this.infix.join('') + ' = ' + suffixRe;
                            this.$history.text(history).attr('title', history);
                        }

                    }
                },

                // 中缀表达式转后缀
                infix2Suffix: function() {
                    var temp = [];
                    this.suffix = [];

                    for (var i = 0; i < this.infix.length; i++) {
                        // 数值，直接压入
                        if (!this.isOp(this.infix[i])) {
                            this.suffix.push(this.infix[i]);
                        } else {
                            if (!temp.length) {
                                temp.push(this.infix[i]);
                            } else {
                                var opTop = temp[temp.length - 1];
                                // 循环判断运算符优先级，将运算符较高的压入后缀表达式
                                if (!this.priorHigher(opTop, this.infix[i])) {
                                    while (temp.length && !this.priorHigher(opTop, this.infix[i])) {
                                        this.suffix.push(temp.pop());
                                        opTop = temp[temp.length - 1];
                                    }
                                }
                                // 将当前运算符也压入后缀表达式
                                temp.push(this.infix[i]);
                            }
                        }
                    }
                    // 将剩余运算符号压入
                    while (temp.length) {
                        this.suffix.push(temp.pop());
                    }
                },

                // 后缀表达式计算
                calcSuffix: function() {
                    this.result = [];

                    for (var i = 0; i < this.suffix.length; i++) {
                        // 数值，直接压入结果集
                        if (!this.isOp(this.suffix[i])) {
                            this.result.push(this.suffix[i]);
                        }
                        // 运算符，从结果集中取出两项进行运算，并将运算结果置入结果集合
                        else {
                            this.result.push(this.opCalc(this.result.pop(), this.suffix[i], this.result.pop()));
                        }
                    }
                    // 此时结果集中只有一个值，即为结果
                    return this.result[0];
                }
            };

            new Calculator('.calc-wrap');
        });
    </script>
</head>

<body>
    <!-- 计算器 -->
    <div class="calc-wrap">
        <div class="calc-in-out">
            <!-- 上一条运算记录 -->
            <p class="calc-history" title=""></p>
            <!-- 输入的数据 -->
            <p class="calc-in"></p>
            <!-- 输出的运算结果 -->
            <p class="calc-out active"></p>
        </div>
        <table class="calc-operation">
            <thead></thead>
            <tbody>
                <tr>
                    <td data-ac="cls" class="cls">C</td>
                    <td data-ac="del">&larr;</td>
                    <td data-ac="sq">x<sup>2</sup></td>
                    <td data-ac="mul">&times;</td>
                </tr>
                <tr>
                    <td data-val="7">7</td>
                    <td data-val="8">8</td>
                    <td data-val="9">9</td>
                    <td data-ac="div">&divide;</td>
                </tr>
                <tr>
                    <td data-val="4">4</td>
                    <td data-val="5">5</td>
                    <td data-val="6">6</td>
                    <td data-ac="plus">+</td>
                </tr>
                <tr>
                    <td data-val="1">1</td>
                    <td data-val="2">2</td>
                    <td data-val="3">3</td>
                    <td data-ac="minus">-</td>
                </tr>
                <td data-ac="per">%</td>
                <td data-val="0">0</td>
                <td data-ac="dot">.</td>
                <td data-ac="eq" class="eq">=</td>
            </tbody>
        </table>
    </div>
</body>

</html>